Case studies - Living Roofs in Integrated Urban Water Systems - page 147

irst of its kind in Portland, and continues to draw community pride and interest
(Timmerman 2014).
5.2.1.2 Materials
All materials used were non-persistent, non-toxic, and procured from reused,
recycled, renewable or ubiquitous sources (for example, PVC products were pro-
hibited). Woods used in the construction were FSC- certiied wood or recycled.
Paints, inishes and materials with low or no VOC emitting properties were uti-
lized to provide high indoor air quality.
5.2.1.3 Resource use and management
Water : the two living roofs and at-grade landscape elements were designed to inte-
grate with the Port's campus-wide stormwater management system, which miti-
gates runoff from all of its land-related infrastructure surfaces (i.e., planes, cars and
buildings). The extensive living roof reduces peak lows, cools runoff temperatures
from the high-temperature roof surface, and captures runoff from the non-
vegetated roof area of the tenth loor's roof, before directing runoff to the campus-
wide system (City of Portland 2010). Runoff conveyance is not exposed, and no
adjacent at-grade GI systems exist to receive the runoff so as not to place birds or
other wildlife at risk from the infrastructural activity of the Port (Timmerman 2014).
The two living roofs were designed to conserve water through retention and
detention and through an eficient irrigation system. The system design ensures
that the need for artiicial irrigation does not signiicantly exceed the amount of
rainfall on or lowing through the site. For the tenth loor extensive living roof, a
temporary, timer-activated artiicial irrigation system (consisting of a standard
pop-up sprinkler system, a 25 mm main, 19 mm and 13 mm feeders) was installed
for plant establishment (City of Portland 2010). Artiicial irrigation was intended
for one to two years and was shut off after plant establishment (Timmerman
2014). The system was retained in case of future replanting needs, and has been
used only in periods of extreme drought. The need for irrigation has been
reduced by a selection of Sexanguiare , Albun and Oreganum species (City of
Portland). This carefully selected mix is drought tolerant, native or adaptive,
requires less water, and is well adapted to the local climate and ecological
context. Reductions in irrigation through xeriscaping thus furthers stormwater
management performance of the roof, while enabling habitat creation for plant
life, invertebrates and pollinators (Timmerman 2014).
Due to the recent construction of the building, no oficial monitoring has
taken place. However, a city audit is to take place in the summer months of
2014, as part of maintaining the criteria for the building's LEED certiication. The
Portland South Waterfront District is also undergoing a community-wide per-
formance assessment, and the aggregated stormwater management perform-
ance data for the neighborhood will become available.
Energy : to aid in energy use reduction, both living roofs are used for their insu-
lative capacity by facilitating the regulation of the internal building temperature.